The present invention relates to apparatuses having display means operable to display data from two or more sources simultaneously, particularly but not exclusively in respective display panels or windows on a single screen or display device, and to methods for managing the presentation and updating of such data displays.
Such multiple source display apparatuses have become a relatively common feature in the past few years, with windows desktops on computers and picture-in-picture facilities on televisions being two well known examples. U.S. Pat. No. 5,680,152 (Bricklin) describes a method and apparatus for navigating multiple independent windowed images on a computer display screen of a computer display system. Whilst the windows may be of an arbitrary shape and size, Bricklin (in common with many other such systems) prefers that they be rectangular.
An On Screen Display (OSD) system for a digital television set-top box is described in European patent application EP-A-0 840 277 (Texas Instruments). The OSD system described can simultaneously display different kinds of pictures, such as a bit-map, a graphic, a still video picture, a motion video picture, or a background colour, with each in a respective window. A random access memory device provides both CPU working memory and a store for the assembled windows in the system of EP-A-0 840 277 with a window controller selectively reading contributions from a selected window to a first-in-first-out memory holding the bits required to display each pixel of the composed screen display.
As hinted at by EP-A-0 840 277, displays may be required to display data not only from several sources, but also from several kinds of source and, as will be appreciated, this can lead to crowding if each source is to inhabit a separate area of the display. Whilst the user operation of selecting a single display panel and zooming out such that it fills the majority (if not all) of the available display space can improve the clarity, it is becoming more common for users to require to have a number of panels or windows open to view at any given time.
It is accordingly an object of the present invention to provide a display system which gives improved volume of display capacity per unit area of display surface.
It is a further, subsidiary, object to provide such a system supporting improved indexing and access facilities for the user.
In accordance with a first aspect of the present invention there is provided an on screen display generation apparatus comprising: two or more independent sources of data for display; a windows controller arranged to generate and periodically update a respective display panel for each source based at least partially on data from that source; first storage means holding data for generated display panels including specification that at least a part of one panel is translucent; and a display controller configured to generate output pixel values for display based at least partially on contributions from two or more of said display panels, with certain pixels having contributions from two display panels where a first panel is positioned to at least partially overlie a second and the overlying part of the first panel is specified as translucent.
By providing for the overlying portion of a display panel to be translucent, the features of the overlain panel can at least partially be seen, thereby making available to the user a greater volume of data.
The windows controller may be arranged to generate each display panel as a first portion and a second, attached, portion with only one of the first and second portions being specified as translucent. In such an arrangement, one of the sources may suitably comprise a source of video image frame sequences and the display panel for that source may then display the video image frames in the portion other than that specified as translucent. Also, such video image source may supply ancillary data to the video image frame sequences and the windows controller may then be arranged to generate content in the portion specified as translucent on the basis of said ancillary data.
One of the sources may comprise a tuner capable of receiving broadcast television signals, and another may be is a web browser configured to obtain from the Internet web pages relevant to a currently displayed broadcast television signal and to present any web pages so found in an at least partially translucent panel overlying that panel on which images from the broadcast television signal are being shown.
The display controller may be arranged to generate a two dimensional image of a three dimensional environment, based on stored data defining said environment, from a predetermined viewpoint within said environment, and with said display panels mapped onto surfaces within said environment. With such an arrangement, user-operable input means are preferably provided by operation of which the user is enabled to manoeuvre the location and/or direction of said viewpoint within the three dimensional environment.
In one embodiment, to be described in greater detail hereinafter, the above-mentioned stored data defining the environment may define a plurality of generally prismatic bodies each having at least a planar face onto which a respective display panel is mapped and an adjacent surface onto which said overlying part is mapped. Such prismatic bodies, which may for example be parallelepidel blocks or objects, may have two or more surfaces adjacent said planar face with each of said surfaces carrying ancillary data to the contents of the display panel, for which arrangement the user operable input means is preferably operable to direct said viewpoint to a user-selected one of said surfaces carrying ancillary data. To further facilitate the indexing of the data panels by the user, the ancillary data on respective surfaces of a prismatic body may be divided into a predetermined number of data categories, with the respective prismatic bodies being arranged such that at least some of the prismatic body respective faces having a given category of ancillary data may be viewed simultaneously from a single viewpoint. In other words, the selection of a particular viewpoint may bring into view the xe2x80x9ctopxe2x80x9d edges of all the blocks on which the authors of the respective works appearing on the display panels are identified, whilst a second viewpoint might show all the left-side edges of the blocks on which the titles of the respective works are identified.
As a further user-settable feature, and by operation of the same or another user operable input means, the user may be enabled to vary the extent of translucency for an overlying portion.
Also in accordance with the present invention there is provided a method for control of on-screen display of data from two or more independent sources of data for display, comprising:
generating and periodically updating a respective display panel for each source based at least partially on data from that source;
storing the generated display panels together with specification that at least a part of one panel is translucent; and
generating output pixel values for display based at least partially on contributions from two or more of said display panels, with certain pixels having contributions from two display panels where a first panel is positioned to at least partially overlie a second and the overlying part of the first panel is specified as translucent.